Telephonic repeating system.



PATENTED FEB. 13, 1906.

A. J. P. BERTSGHY. TELEPHONIG REPEATING SYSTEM.

APPLICATION FILED JUNE 4,1904.

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No. 812,718. PATENTED FEB. 13, 1906.

A. J. P. BERTSGHY.

TELEPHONIO REPEATING SYSTEM. APPLICATION FILED JUNE 4,1904.

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r T A PATENTE'D FEB. 13, 1906.

A. J. P. BERTSGHY. TELEPHONIC REPEATING SYSTEM.

APPLICATION FILED JUNE 4,1904.

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currents in the first circuit.

- UNITED STATES ADOLPH J. P. BERTSCHY, OF WOODSTOCK, ILLINOIS, ASSIGNOR OF ONE- PATENT OFFICE.

FOURTH TO CHARLES H. DONNELLY. OF W OODS'lOLK,ILLINOIS.

TELEPHQNIC HEPEATING SYSTEM.

Specification of Letters Patent.

Patented Feb. 13, 1906.

Application filed J 1110 4, 1904. Serial No. 211,147-

To ml]; .whom it may concern.-

Be-it known that I, ADOLPH J. P. BERTSCHY,.

Woodstock, in the county of McHenry and State of Illinois, have invented a certain new and useful Improvement in Tele honic Reeating Systems, of which the fo owing is a all, clear, concise, and exact description, reference being had, to the accompanying drawin s, forming a part of this specification.

y invention relates to variable-current repeaters, and is particular] useful as an in tensifying-repeater for telephonic urposes.

*As is well known to those skille in the art, the transmission of alternating or pulsating telephonic voice-currents to a great distance is accompanied by a considerable attenuation of the current-waves, which so far reduces the intensity of the vibrations at the receiving end as to render the long-distance trans mission of telephonic voice-currents a matter of extreme difficulty. It has heretofore been the practice to repeat tele aphic currents by means of relays, a relay ein connected in one circuit so asto be control ed by the cur rents flowing in this circuit and the armature of the rela controlling, by means of suitable contacts, t e currents fiowin in a second circuit extending beyond. the st. B means of a relay of thisv character itis possib e to control a comparatively strong current in a second circuit by means of comparatively feeble It has heretofore been proposed to repeat telephonic voicecurrents in a manner somewhat similar. It has, for instance, been roposed to mechanically associate a telep lione-receiver and a telephone-transmitter and to connect the receiver-coils at the extremity of one telephonic circuit, the receiver-coils serving to. actuate, by means of variations of current flowing therein, the resistance-varying members of the associated transmitter, the transmitter serving to initiate telephonic current-waves in a second transmission-circuit extending beond the terminal of the first transmissionine. While such combined receivers and transmitters of the rior art have not been suitably constructe for the purpose, they have also been subject to the very serious objec'tion that they provide for the transmis sion of voice-currents in one direction only. It has been attempted from time to time to provide systems in which the voice-currents could be transmitted over a single pair of conductors in both directions, this of course being a well-known commercial requirement. Great difficulty has been experienced in making a two-way repeater, for the reason that no automatic switch has been devised which would bring about the circuit changes required when the transmitting-station desired to become the receiving-station. It has been attempted to associate two relays with the line-circuits in such a manner that no interference would occur. The great and thus far insurmountable difficulty in connection with such'systems of the prior art has been that the two relays when associated with the same pair of lines would almost invariably set u a singing sound, due to the mutual action lietween the two. phragm ofone relay would produce changes in the current in the local circuit which would act upon the diaphragm of the other relay, producing another change of current, which would in turn react upon the first relay. This action isin'many respects analogous to that produced in many telephone-circuits by holding the receiver of a telephone set in front of the mouthpiece of a microphone-transmitter. The shrieking noise set up when this adjustment is made is due to the fact that the soundwaves set up by the receiver-diaphragm act upon the transmitter-diaphragm, which in turn causes currents to flow through the receiver-coil, causing its diaphragm to vibrate still more strongly, andthus in turn againto set up further vibrations in the transmitterdiaphragm. My invention provides means for overcoming these difficulties heretofore experienced, the invention residing partially in the construction of the repeater and other mechanism employed and partially in the circuit arrangements by means of which automatic switches serve to provide for the transmission of voice-currents in either direction without interference, which will produce the shrieking or howling above described.

My invention will be clearly understood by reference to the accompanying drawings, in which Figure 1 illustrates diagrammatically the a paratus-and circuit connections employed.

ig. 2 illustrates the telephonic relay. Fig. 3 illustrates a combined induction-coil and electromagnetic switching device. Fig. 4 illustrates a double-contact relay, which is A slight vibration of the (is.

used in the referred embodiment of my invention; and Fig. 5 illustrates a olarized relay, which is used in bringing a out certain desired circuit changes.

I shall first explain the various pieces of apparatus employed and then describe the manner of their cooperation by means of Fig. 1.

Referring now more particularly to Fig. .2, I shall describe in detail the telephonic repeater, which forms a part of my invention. Broadly stated, this figure shows the combination of a telephone-receiver with a microphone-transmitter; but the construction of my invention embodies many points of novelty and value. A diaphragm 11, preferably of ferrotype iron, is common to the receiver and transmitter portions of the telephonic relay or repeater. This diaphragm is provided with a soft-rubber gasket 12, clamped between the two clamping-rings 13 and 14, these rings being screwed into the threaded end of the cylindrical metal shell 15, whereby the position of the diaphragm may be adj usted within the shell. The permanent horseshoe-magnet 16 is provided with soft-iron pole-pieces 17 and 18, upon which are wound the receiver magnet-coils 19 and 20, the poleieces being near the receiver side of the soft- 1ron diaphragm 11. The permanent magnet 16 is secured to a table 21, this table being pivoted at 22 to a suitable standard 23, the thumb-screw 24 serving to clamp the table in position. The receiver is attached to the end plate 25 of the chamber which incloses the repeater mechanism proper. By turning the shell 15 upon this end plate the distance between the pole-pieces 17 and 18 and the diaphragm 11 may be adjusted, the locking-ring 26 serving to clamp the parts in adjustment. The receiver-coils are not con nected together, as is generally done; but the inner ends of the coils are connected through the insulated leading-in studs, with the terminals 27 and 28. The outer terminals of the coils are connected by way of suitable leading-in studs with the terminals 25) and 30. Upon the face of the diaphragm 1 1 is soldered a platinum contact-piece 31. This contactpiece normally makes connection with the platinum contact-point of an adjustable contact-screw 32, the position of this screw being regulated by the geared connection with the thumb-wheel 33. The spindle 34, associated with this thumb wheel, extends through a packing-gland 35 and the standard 23 to a pin-wheel 36, splined upon the contact-screw 32, but insulated therefrom. The contact-screw 32 is electrically connected, by means of the metal bearing 37 and a suitable conductor, with a terminal 38, while the contact 31 is connected by way of the diaphragm itself, a suitable conductor, and the leading-in stud 39 with the terminal 40. A suitable bracket 41, of insulating materialsuch as, for instance, hard rubberis attached to the diaphragm 11 a slight distance from the cent-er, and into the hub of this bracket is screw-threaded the stem 42, connected with the movable electrode 43 of the microphone-transmitter button. This button com )rises a chamber 44, to the front or open en of which is clamped the auxiliary mica diaphragm 45, this diaphragm permitting the movement of the movable electrode 43 with reference to the chamber and at the same time retaining the comminuted materialsuch, for instance, as the carbon granules 46within the chamber. The fixed electrode 47 is carried upon a screw-threaded stem 48, extending to the outside of the inclosing case 15. The transmitterbutton as a whole is carried upon the stem 49, this stem being adjustable within the standard 50, which is secured to the hard-rubber end plate 51 of the large cylindrical chamber. The set-screws 52, together with their locknuts, permit the adjustment of the granule chamber and serve to clamp the stem 49 in position. The stem 48 permits the relative adjustment of the fixed and movable electrodes, the lock-nut 53 serving to clamp the parts in permanent adjustment. The movable electrode is electrically connected, by way of the stud 54, with the terminal 55, while the conductor 56 electrically connects the fixed electrode 47 to the terminal 57. The thumb-screw 58 serves to regulate the inclination of the repeater, as I have found that the apparatus is more sensitive when in an inclined position than when in a horizontal position. The repeater as a whole is mounted, by means of the standard 23 and the base 59 for the thumb-screw 58, upon a suitable platen 60, through which there is an opening 61, the pipe,62 registering with this opening and being connected with a vacuum-pump, by means of which the air may be withdrawn from the chamber formed within the bell glass or cover 63, resting upon a suitable gasket 64 upon the platen 60. This cover may be formed of iron, if. desired, to prevent the effect of outside magnetic disturbances.

In F 3 I have illustrated an inductioncoil comprising the core 70, of soft-iron wires, upon which are wound the primary winding 71 of coarse turns of wire and the secondary winding 72, consisting of a large number of turns of fine wire. At one end'of the core an armature 73 is mounted within the trunnions 74. To the armature is fastened a short electromagnet-core 75, upon which the coils 76 and 77 are wound, these coils being connected together at 78 and with the terminals 79 and 80. The conductors leading to the coils 76 and 77 are extremely flexible, so that they will not interfere wit the move ment of the coils and their core with the armature 73. The armature is provided with platinum contact-points at its upper end, these contact-points serving to make connection alternately with the contact-points of the insulated and adjustable contactscrews 81 and 82. An adjustable screw 83 serves to regulate the tension of the retracting-spring 84. A permanent magnet 85 is adjustably mounted within the frame 86 and upon its front end carries an electromagnetcoil 87. The various electrical terminals and contacts are connected with suitable bindingposts, as shown, the entire mechanism being mounted upon a suitable base-plate 88.

In Fig. 4 I have illustrated a double-com tact relay, comprising an ordinary electro magnet 90 and an armature 91, this armature being extremely light, as shown. An adjustable screw 92 regulates the tension of the retracting-spring 93, the armature serving normally to make electrical connection with the back contact-screw 94, but when attracted, due to the energization of the electromagnet 90, to make contact with the contact-screw 95, this contact-screw being connected directly with the frame 96. The electrical connections with the various binding-posts are indicated in the figure.

- In Fig. 5 I have shown a polarized doublecontact relay comprising electromagnets and101, these magnets being mounted between the poles 102 and 103 of a permanent magnet 104. The armature 105 is mounted in suitable trunnions 106 and vibrates between the electrical contact-screws 107 and 108. Suitable binding-posts mounted upon the base 109 are provided for the purpose of making the required electrical connections with the coils and contacts. The construc'- tion of all these relays should be made extremely delicate, the trunnions being provided with hardened-steel journals and jeweled bearings in order that the adjustment may be perfected and the movement of the armatures accompanied with the least possible friction, the reason for this being that the movements of the armatures must take place with extreme rapidity, as will hereinafter more fully appear.

I shall refer now more particularly to Fig. 1, in which the circuit connections of these various fpieces of apparatus are shown, the parts 0 the apparatus diagrammatically shown in Fig. 1 corresponding with the a paratus shown in Figs. 2 to 5, inclusive. T ese parts diagrammatically illustrated in Fig. 1 are provided with the same reference characters as those illustrated in the figures, more fully showing the precise mechanical construction employed. At A and A are illustrated telephonic repeaters or relays, such as shown in detail in Fig. 2. At B B are shown induction-coils and electromagnetic armature mechanism, such as shown in Fig. 3. The relays marked C and O in Fig. 1 are like that shown'in Fig. 4, and the relays D and D of Fig. 1 are of the type shown in Fig. 5.

In Fig. 1 I have illustrated subscribers substations at E and F, the substation E being connected with the spring-jack terminals 9 and h by means of the telephone-line limbs j and i. The substation F is connected with the spring-jack terminals in and Z by means of the line-limbs m and n. Between the springjack terminals of the line to station E and the spring-jack terminals of the line to station F is interposed the repeating mechanism which constitutes my invention. The repeating outfit is connected between the terminals 0 and p of the plug g and the terminals r and s of the plug t.

It may be stated in general that the repeating apparatus which is employed in transmitting telephonic voice-currents in one direction is duplicated by similar apparatus employedv in transmitting voice-currents in the opposite direction. Switching mechanism is provided which serves to open the circuit connections required for transmission in one direction when transmission is being carried on in the other direction, and my invention contemplates the use of a double series of safeguards to prevent simultaneous connection of the re eating apparatus in such a manner as would permit interference and shrieking due to undesirable cooperation of the two repeating-relays employed.

I shall now trace the circuits employed in the operation of the repeating system. There is a permanent connection b means of the conductor 110 between the s eeve-contact p of plug g and the coil 19 of the repeating-relay A. The circuit throu h this coil and its mate 20 is traced norma 1y from coil 19, through the terminal 28, (shown on Fig. 2,) through the conductor 111 (shown on Fig. 1) to the armature 73 of the electromagnetic switching device B, the front contact 81 of this rela the conductor 112, the receivercoil 20 o the repeaterA, and thence through conductor 113, armature 105 of the polarized relay D and its normal contact 108 to the tipcontact 0 of the plug q. The voice-currents entering the repeating system from the line from station E traverse this circuit, thereby setting in vibration the diaphragm 11 of the repeater A. The diaphragm normally makes connection by means of its platinum contact 31 (shown on Fig. 2) with the contact-screw 32; The following circuit may be traced normally through these contacts: from the positive pole'of the battery 114 to diaphragm 11, contact 32, through conductor 115 to the electromagnet 90 of relay C, ;and thence through conductor 116 back to the negative pole'of the battery 114. Currentpassing through this circuit normally closes a circuit from the local battery 117 through the armature 91 of relay C, its front contact 95, and through the electroma net-winding 101 of relay D" to the other si e of the battery.

The armature 105 of the relay D is thereby maintained normally in connection with its contact 108.

The voice-currents set up at substation E maybe in the nature of variations of an otherwise steady current flowing through the coils 19 and 20. When, therefore, the-diaphragm is set in vibration by means of the variable currents passing through the coils 19 and 20, the current traversing the local circuit throu h the coil of the relay C is interruptec on account of the breaks in the circuit introduced between the contact-points 31 and 32 on the face of the repeater-diaphragm 11. The retracting-spring 93 is of sufiicient tension to retract the armature 91 from its front contact 95, and as the interruptions in the circuit through the coil 90 are of great frequenc the armature 91 is retained in electrica connection with its back contact 94 during the period in which the diaphragm 11 of the repeater A is vibrating due to passage of voice-currents coming in from station E. -The retraction of the armature 93 from the front contact 95 serves to break the circuit previously traced through the electromagnet coil 101 of the relay D, and the connection of the armature 93 with back contact 94 closes a similar local circuit through the electromagnet of the polarized relay D, whereupon the armature 105 is attracted to make connection with its alternate contact 107. This movement of the armature 105 serves a double purpose-first, to break a circuit which could otherwise be traced from the tip-contact r of the plug t through the contact 108, the armature 105, conductor 113, and thence through the receiver-coils of repeater A back to the sleeve-contact s of the plug t. This circuit is similar to that already described for the other side of the repeating system and is the one which would serve to actuate the diaphragm 11 of the repeater A in receiving voice-currents from station F. The interruption of this circuit by means of the break introduced between the armature 105 and the contact 108 serves to prevent the passage of currents through the coils 19 and 20 of the repeater A during the time in which the re peater A is in operation for the transmission of voice-currents from the line from substation E to the line to substation F. Furthermore, the connection of the armature 105 with the contact 107 closes the secondary circuit of the induction-coil of the instrument B to the line F. This circuit may be traced as follows: from the secondary coil 72 of the induction-coil at B, through conductor 118 to armature 105, thence to contact 107, sleevecoritact s of plug t, and after passing through the line to station F, to tip-contact r of the pin 15, and thence through conductor 119 bac to the other side of the secondary 72. As will now be explained, it is the currents from this secondary 72 of the induction-coil B that are transmitted to the station F. The primary coil 71, inductively related to the secondary coil 72 of the instrument B, is connected through a local battery 120 with the electrodes of the transmitter-button 44 of the repeater A. The vibrations of the diaphragm 11, due to voice-currents coming in from station E and traversing the coils 19 and 20, cause variations in the resistance of the granules between the electrodes of the button 44, whereupon similar voice-currents are set up in the primary winding 71, thereby inducing similar voice-currents but of higher intensity in the secondary coil 72, and these voice-currents are transmitted through the circuit already described to station F.

If desired, a second repeating system may be connected at station F, this second repeater serving to intensify and repeat the voice-currents to the third station, and so on indefinitely.

In shunt of the transmitter-button are connected the electromagnet-coils 76 and 77 of the instrument B, these coils all wound upon a core 75, as shown in Fig. 3, the whole being mounted with the armature 73. A certain current flows normally through the primary winding 71, thereby polarizing the soft-iron core 70 of the induction-coil, and a certain current flows also through the electromagnet-coils 76 and 77, whereupon the armature 73 remains normally in electrical connection with the contact 81. When the granules within the transmitter-button 44 are compressed, there is a conse uent decrease in the resistance, whereupon tie transmitter-button serves to shunt an increased proportion of the current from the electromagnet-coils 76 and 77, and there will also be a slight increase in current through the coil 71. This increase in current in the coil 71, however, is not suflicient to overcome demagnetization of armature 73 and the attraction of said armature by the permanent magnet 85. The armature therefor is drawn into engagement with contact 82. This movement of the armature 73 of the instrument B serves two purposes-first, to break the connection between the contact 81 and the armature 73, a circuit through these contacts being required for the operation of the diaphragm 11 of repeater A, due to voice-currents traversing the associated coils 19 and 20. In other words, when the diaphragm 11 of the repeater A is set in o eration the armature 73 of the instrument at once breaks its connection with the contact 81, thereby preventing the operation of the repeater A, Thus when the re eater A is in operation there are two breaks in the circuit through the coils 19 and 20 of the repeater A to prevent the operation of this repeater, one of these breaks beingmade between the contact 108 and the armature 105 of the polarized rebetween the armature 73 and its contact 81 of the instrument B. When the armature 73 makes connection with its back contact 82, a local circuit is closed from the local battery 121 through the electromagnet-coil 87 of the electromagnetic device B and thence through conductor 122 to contact 82 of the instrument B. Current flowing through this circuit is in such a direction as to depolarize the permanent magnet 85 of the instrument B, whereupon the attraction for the core 75, associated with the armature 73 of the instrument B, is decreased to such an extent as to absolutely insure the armature 73 of instrument B making connection with its contact 81. It will be remembered that this circuit is absolutely essential for the operation ofthe repeater A, as the circuit through its, coils 1.9 and was traced through a connection between this armature 73 and its contact81 of instrument B. E has ceased talking, the normal current is caused to flow through the coils 19 and 20 of repeater A, this current being of a zero value, if so desired, and in this case the voice-currents serve to depolarize the permanent magnet 16 of the repeater.) ar-iations in the resistance of the transmitter-button 44 are therefore discontinued, whereupon a steady current of increased value flows through the coils 76 and 77 of the instrument B and the armature 7 3 is attracted to make connection with its normal contact 81. The diaphragm 11 makes an uninterrupted electrical con nection with its contact-screw 32, whereupon a circuit for uninterrupted currents is closed through the electromagnet of the relay C the armature 91 being thereupon attracted to make connection with. the contact 95, which closes a local circuit through the winding 101 of the relay D, whereupon the arma ture 105 is attracted to engage the contact,

108, thereby restoring the instruments to their normal condition.

As heretofore pointed out, the subscriber at station Fcannot cause the operation of his repeater A during the time in which the repeater A is in operation, due to voice-currents coming in from station E but with the cessation of voice-currents cumin in from station E the apparatus is restored to its normal condition such that a subscriber at station F may cause the operation of the repeater A to 19 and 20 of the repeater A by way of the When a person at station circuit aflordedbetween the connected contact 81 and the associated armature 73 of the instrument B. Currents pass from the coil 20 to the tip-contact r by way of the conductor 113, the armature 105 of polarized relay D, and the contact 108. These voicecurrents traversing the coils 19 and 20 of the repeater A set in vibration the associated diaphragm 11 thereby breaking the otherwise completed circuit through the diaphra m 11 and the associated contact-screw 32 0 the repeater A, the current throu h this circuit normally flowing through 't e electromagnet 90 of the relay C by way of conductor 115, the battery 114, and the conductor 116. The deener ization of the electromagnet 90 of the relay 1 causes the retraction of the associated armature 91 to break the local circuit through the coil 101 of the polarized relay D and to close the circuit through the electromagnet 100 of this relay, thereby causing the attraction of the armature 105 to break the connection with the contact 108 and to make connection with the alternate contact 107. It will be remembered that the circuit previousl traced from station E to repeater A include a connection between the contact 108 and the armature 105; The breaking of this connection upon the actuation of the repeater A 'for transmission in the opposite direction prevents the subscriber at station E and the repeater A itself from interfering with the transmission from station E to station E. The closure of the connection between contact 107 and armature 105 provides a circuit from the secondary winding 72 of the instrument B through conductor 118, armature 105, contact 107, sle evecontact p of the plug q, and thence to station E, the return-circuit being traced through the contact o of the plug g and conductor 119 to the other side of the secondary 72 of instrument B. Thus the vibrations of the diaphragm-11 oi the repeater A caused by voice-currents coming in from station F when )roducing variations in the resistance of the associated transmitter-button 44 may cause an intensification and repetition of the voice-currents to station E on accou'ntof the inductive relation between the secondary coil 7 2 of the instrument B and the associated primary coil 71, which is connected with the electrodes of the button 44 of the re eater A. The local circuit for primary coi 71 oi instrument B includes a source of current 120, this-battery supplying current also to the coils 7 6 and 77 of the instrument B, as already described in connection with the instrument B. The compression of the granules within the button 44 of the repeater A causes/a decrease in the resistance thereof, whereupon the coils 76 and 77 of instrument B are deprived of a portion of their current, thereby causing a movement of the armature 73 to break connection with the normal contact 81 (this connection being essential for the operation of the re eater A) and making connection with the a ternate contact 82, this connection serving to depolarize the permanent magnet 85 of the instrument B in the manner already described, thereby insuring the main tenance of the connection between the armature 73 and the front contact 81 of the instrument B, (this connection being essential for the operation of the repeater A.) 4

At 130 and 130 I have shown tertiary induction-coil windings, to which an operators telephone set may be connected for the purpose of supervision. Any suitable system of supervisory or other signals ma be associated with the cord-circuit to w ich the repeating system is connected, these signals being employed in the well-known manner for affording control of the connections. Under certain conditions I have found it desirable to place certain of the rela s in addition to the repeating-relays A an A in vacuumchambers-such, for instance, as that shown in Fig. 2. Such a provision permits the more prompt and rapid movements required of the armature mechanism.

Most of the parts diagrammatically illustrated in Fig. 1 are mechanically constructed as shown in Figs. 2 to 5, inclusive, and where such correspondence exists the same reference characters are applied to the parts of Fig. 1 as in Figs. 2 to 5, inclusive. The sources of current and conductors shown in Fig. 1 are duplicated for transmission in both directions, and these duplicate parts are provided with similar reference characters,

except that in one case the reference charactersare rovided with a suitable index.

It wilFbe seen that by means of my invention telephonic voice-currents may be repeated and intensified in both directions over a single transmission-circuit, the transmission being effective without interference and without the loss of clearness, but with increased intensity, whereby telephonic transmission may be carried on to eat distances and through obstacles-such, or instance, as submarine cableswhich heretofore have offered a considerable obstruction to the transmission of telephonic currents.

WVhile I have herein shown and described a preferred embodiment of my invention, it will be understood by those skilled in the art that many modifications and changes may be made without departing from the spirit thereof. I do not wish, therefore, to limit myself to the precise construction herein set forth; but,

Having described my invention, I claim as new and desire to secure by Letters Patent 1. In a telephonic repeating system, the combination with two transmission-lines terminating at a repeating-station, of a repeatin -relay for each line, each comprising suitab e receiving-coils, a transmitter and a common vibratory diaphragm, a transformer associated with each repeating-relay, the pri-. mary circuit of each transformer being controlled by the transmitter of the associated repeating-relay, an electromagnetic switching device for each repeating-relay, each having an actuating-winding connected in shunt of the transmitter thereof, each of said switching devices serving normally to maintain the closure of a break in the circuit of the receiving-coils of the other repeating-relay but when actuated due to the actuation of the associated transmitter to open the break in said receiver-circuit, each of said switching devices serving also when actuated to close a local circuit through an electroma netic safety device associated with the ot er switching device, thereby insuring the maintenance of its normal circuit connections, and an auxiliar switching device associated with the diaphragm of each repeating-relay and each maintaining normallya closed circuit throu h associated electromagnetic switching mec anism, said electromagnetic switching mechanism serving norma ly tomaintain an electrical connection between the receiving-coils of the other repeating-relay and its transmission-line and to maintain a break in an. otherwise completed circuit containing this other transmission-line and the secondary coil of the transformer associated with that relay which controls the given switching mechanism, but serving when deenergized due to the opening of the circuit at said auxiliary switching mechanism. upon the vibration of the associated relay-diaphragm to close the circuit connection between said transmission-line and thesecondary coil of said transformer and to open the circuit connection between the same transmission-line and the receiving coils of its repeating-relay.

2. In a telephone repeating system, the combination with an electromagnet connected in a receiving-circuit, of a transmitter for controlling currents in the sending-circuit, a vibratory diaphra m common to said electromagnet and said transmitter, and an auxiliaryswitching device controlled bysaid diaphragm to cause the closure of a break in the sending-circuit.

3. In a telephonic repeating system, the combination with an electromagnet connected in a receiving-circuit, of a transmitter for controlling currents in the sending-circuit, a vibratory diaphragm common to said elec- 'tromagnet and said transmitter, normally closed switch-contacts associated with said diaphragm, an electromagnetic switching device controlled by said switch-contacts, and means whereby the vibration of said diaphragm causes a break in the connection between said switchc,ontacts to decnergizc said electromagnetic switching device, said switching device serving normally to maintain a break in the sendin -circuit but upon deenergization to cause t e closure of said break in the sending-circuit.

' 4. In a telephone repeating system, the combination with electromagnetic receivingcoils connected in a receiving-circuit, of a transmitter for controlling currents in the sending-circuit, a vibratory diaphragm common to said electromagnetic receiving-coils and said transmitter, a relay having one electromagnet adapted upon energization to cause the associated armature to assume one ofits alternative positions, and a second electromagnet adapted upon energization to cause thearmature to assume the other of its alternative positions, the armature remaining in the position which it has assumed due to the energization of either electromagnet until the other electromagnet is ener.

gized, a second relay adapted upon energiza tion to cause a closure of the circuit through the first electromagnet of the first said relay, and upon deenergization to cause the closure of a local circuit through the second electromagnet of the first said relay, and auxiliary switch-contacts associated with said diaphragm, said switch-contacts serving normally to maintain the closure of a circuit through the second said relay, but upon the vibration of said diaphragm to interrupt the circuit through said relay, the energization of the second electromagnet of the first said relay serving to close a break in the continuity of the sending-circuit.

5. In a telephone repeating system, the combination with electromagnetic receivingcoils connected in a receiving-circuit, of a transmitter for controlling currents in the sendingcircuit, a vibratorydiaphragm common to said electromagnetic receiving-coils and said transmitter, a relay having one electromagnet adapted upon energization to cause the associated armature to assume one of its alternative positions, anda second electromagnet adapted upon energization to cause the armature to assume the other of its alternative positions, a second relay ada ted upon energlzation to cause a closure 0' the circuit through the first electromagnet of the first said relay and upon deenergization to cause the closure of a local circuit through the second electromagnet of the first said relay, and auxiliary switch-contacts associated with said dia )hragm, said switch-contacts serving normaily to maintain the closure of a circuit through the second said relay but upon the vibration of said diaphragm to interrupt the circuit through said relay, the en ergization of the second electromagnet of the first said relay serving toclose a break in the continuity of the sending-circuit.

6. In a telephonic repeating system, the combination with two transmission lines leading to a repeating-station, of a repeating relay for each line, each relay having its receiving-coils normally connected with one line and its transmitter'adapted for the control of voice-currents in the Ofihfil llllfl, and

electromagnetic switching mechanism controlled by said repeating-relays, whereby the actuation of one of said relays serves to open the circuit through the receiving-coils of the other relay.

7. In a telephonic repeating-station, the combination with two transmission lines leadin to a repeating-station, of a repeatingrelay or each line, each relay having its receiving-coils normally connected with one line and its transmitter adapted for the control of voice-currents in the other line, and electromagnetic switching mechanism controlled by said repeating-relays, whereby the actuation of one of said relays serves to open the circuit through the receiving-coils of the other relay and to close the transmitting-circuit of the first-named relay.

8. In a telephonic repeating system, the combination with two transmission lines leadin to a repeating-station, ofa repeatingrelay for each line, each relay having its receiving coils normally connected with its line and its' transmitter adapted for the conleadin to a repeating-station, of a repeatingrelay or each line, each relay having its re ceiving-coils normally connected with its line and its transmitter adapted for the control of voice-currents in the other line, and switching mechanism controlled by said repositing-relays, whereby the actuation of one of said rela s serves to cause a plurality of breaks in the circuit through the receiving coils of the other relay and to close the transmitting circuit of the first-named relay.

10. In a telephonic repeating system, the combination with two transmission lines leading to a repeating-station, of a repeatingrelay for each line, each relay having its re ceiving-coils connected with'its line and its transmitter ada ted to control inductively the currents intiie other line, and an electromagnetic switching device connected in shunt of said transmitter and serving upon partial denergization due to a decrease in resistance in the transmitter to break the circuit ithrough the receiving-coils of the other re- 11. In a telephonic repeating system, the combination with two transmission-lines leading to a repeating-station, of a repeatii'ig-relay for each line, each relay having its receiving-coils connected with its line and its transmitter adapted to control inductively the currents in the :other line, an electromagnetic switching device connected in shunt of said transmitter and serving upon partial deenergization due to a decrease in resistance in the transmitter to break the circuit through the receiving-coils .of the other relay, and auxilliary switch-contacts controlled by the vibra tion of the diaphragm of each repeating-relay, said switch-contacts serving'to control the transmitting circuit of the first-named re- 12. In a telephonic repeating system, the combination with a pair of transmission-lines terminating at a repeating-station, of a repeating-relay for each line, an induction-coil for each repeating-relay, the circuit for the primary coil of each induction-coil being controlled by the transmitter of one of said repeating-relays and'the secondary coil of each induction-coil being adapted for connection with one of said transmission-lines but normally disconnected therefrom, and means whereby the passage of telephonic voice-currents from one line to its re )eating-rela causes a connection of the secondary coil of t e associated induction-coil with the other transmission-line.

13. In a telephonic repeating system, the combination with a pair of transmission-lines terminating at a repeating-station, of a repeating-relay for each line, an induction-coil for each re eating-relay, the circuit for the primary coi of each induction-coil being controlled by the transmitter of one of said rcpeating-relays, the secondary coil of each induction-coil being adapted for connection with one of said transmission-lines but normally disconnected therefrom, and means whereby the passage of telephonic voice-currents from one line to its repeating-relay causes a connection of the secondary coil of the associated induction-coil with the other transmission-line and causes a break in the connection between this other transmissionlirie and the receiving-coils of its repeatingre ay.

14. In a telephonic repeating system, the combination with a pair of transmission-lines terminating at a repeatingstation, of a reeating-relay for each line, an induction-coil or each repeating-relay, the circuit for the primary coil of each induction-coil bein controlled by the transmitter of one of said re-' peating-relays, the secondary coil of each induction-coil being adapted for connection with one of said transmission-lines but normally disconnected therefrom, and means whereby the passage of telephonic voice-currents from one line to its repeating-relay causes a connection of the secondary coil of the associated induction-coil with the other transmission-line, and causes a double break in the circuit of the receiving-coils associated with this other transmission-line.

15. In a telephonic repeating system, the

combination with a pair of repeating-relays each consisting of a receiver and a transmitter part, of means jointly controlled by said receiver and transmitter part for causing the actuation of one relay to render the other relay inoperative.

16. In a telephonic repeating system, the combination with a pair of repeating-relays, each comprising a transmitter portion and a receiver portion and avibratory member common to both, of switching means associated with said vibratory member, and an electrical circuit controlled by said switching means, whereby the vibration of the vibratory member of one repeating-relay renders the other relay inoperative.

17. In a telephonic repeating system, the combination with a pair 'of repeating-relays, each comprising a transmitter portion and a receiver portion and a vibratory member common to both, of normally closed switch-contacts associated with said vibratory member, and means whereby the vibration of said vibratory member due to voice-currents traversing the associated receiver portion causes the actuation of said switch-contacts to cause a break in the receiver-circuit of the other repeating-relay.

18. In a telephonic repeating system, the combination with a pair of repeating-role, s, each comprising a transmitter portion an a receiver portion and a vibratory member common to both, of normally closed switch-contacts associated with said vibratory members and means whereby the vibration of said vibratory member due to currents traversing the associated receiver portion causes an actuation of said switch-contacts to close the transmission-circuit for the associated transmitter.

19. In a telephonic repeating system, the combination with a pair of repeating-relays,

' each comprising a transmitter portion and a receiver portion and a vibratory member common to both, of normally closed switchcontacts associated with said vibratory member, and means whereby the vibration of said vibratory member due to currents traversing the associated receiver portion causes an actuation of said switch-contacts to close the transmission-circuit for the associated transmitter and to cause a break in the receivercircuit of the other repeating-relay.

20. In a telephonic repeating system, the combination with two telephone transmission-circuits, of a repeating-relay for each circuit adapted to repeat into the other circuit, each relay consisting of a receiver and a transmitter part, and electromagnetic means jointly controlled by the receiver and transmitter parts whereby the actuation of one repeater destroys the connection between the other repeater and its transmission-circuit.

21. In a telephone repeating system, the combination with a pair of transmission-lines terminating at a repeating-station, of a repeating-relay for each line consisting of a receiver and a transmitter part and having its receiving-coils normally connected in circuit with its line, and electromagnetic means jointly controlled by the receiving and transmitting parts whereby the passage of voicecurrents through the receiving-coils of one repeating-relay causes a disconnection of the receiving-coils of the other repeating relay from its transmission-line.

22. In a telephone repeating system, the combination with a pair of transmission-lines terminating at a repeating-station, of a repeating-relay for each line consisting of' 'a receiver and a transmitter part and having its receiving-coils normally connected in circuit with its line, and electromagnetic means jointly controlled by the receiving and transmitting parts whereby the passage of'voicecurrents.through' the receiving-coils of one repeating-relay causes a disconnection of the receiving-coils of the other repeatingrelay from its transmission-line and causes a con nection of the transmitting-circuit of the first said relay with the transmission-line from which the receiving-coils of the other relay are disconnected. I

' 23, In a telephonic repeating system, the combination with two transmission lines leadin to a re sting-station, of a repeatingrelay or each ine, each relay consisting of a receiving and a'transmitting part and having its receiver-coils normally connected with its line, and electroma netic switching mechanism jointly controlIed by the receiving and transmitting parts whereby the actuation of one of said relays serves to open a circuit through the receiver-coils of the other relay.

24. In a telephonic repeating system, the combination with a .pair of transmlssion-lines terminatin at a repeat' station, of a repeating-re a for each ine, transformer means for in uctively transferring telephonic voice-currents from one line to the other, the primary currents through said transformer means being controlled b said repeating-relays, the secondary win ings of said transformer means being ada ted for connection with said transmissionines but normally disconnected therefrom, and means whereby the assage of telephonic voicecurrents from one ine to its repeating-relay causes the closure of a telephonic circuit including said transformer means from the transmitter portion of said repeating-relay to the other transmission-line.

25. In a telephonic repeating system, the combination with a pair of transmission-lines terminatin at a repeatin -station, of a repeating-re ay for each line; transformer means for inductively transferring telephonic voice-currents from one line to the other, the primary currents through said transformer means being controlled by said repeating-relays, the secondary windings of said transformer means being ada ted for connection with said transmissionines but normally disconnected therefrom, and means whereby the passage of telephonic voice-currents from one line to its repeating-relay causes the closure of a telephonic circuit including said transformer means from the transmitter portion of said repeating-relay to the other transmission-line and causes a break in the connection between this other transmissionline and the receiving-coils of its repeatingrelay.

26. In a telephonic repeating system, the combination with a pair of transmission-lines terminatin at a repeatin -station, of a' repeatin -re ay for each ine, means or inductively transmitting telephonic voice-currents from one line to the other, the primer currents through said transformer means eing controlled by said repeating-relays, the secondary windings of said transformer means being ada ted for connection with said transmissionines but normally disconnected therefrom, and means whereby the passage of telephonic voice-currents from either line to its repeating-relay causes the closure of a circuit from the secondary windings of said transformer means to the other transdisconnected therefrom, and means whereby the passage of telephonic voice-currents from either line to its repeating-relay causes the closure of a circuit from the secondary windings of said transformer means to the other transmission-line and causes a break in the connection between this other transmissionlirie and the receiving-coils of its repeatingre a II)! witness whereof I hereunto subscribe my name this 23d day of May, A. D. 1904.

ADOLPH J. P. BERTSCHY.

Witnesses:

LYNN A. WILLIAMS, ARTHUR H. BOETTCHER.

transformer I 

